Cabinet including optical bulkhead plate for blown fiber system

ABSTRACT

A cabinet is provided for managing the connections between a feeder cable and a distribution cable wherein the distribution cable is a blown optical fiber. The cabinet includes shelves for holding splices between the feeder cable and the distribution cable. The shelves also include microduct holders for holding each of the microducts associated with the distribution cable.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.11/970,439 filed on Jan. 7, 2008, which is a divisional of U.S. patentapplication Ser. No. 11/249,726 (now U.S. Pat. No. 7,330,626) filed onOct. 13, 2005, which claims the benefit of U.S. Provisional ApplicationSer. No. 60/713,622, filed Aug. 31, 2005. The disclosures of all of theabove identified applications are hereby incorporated by reference intheir entirety.

FIELD OF THE INVENTION

The present invention relates to fiber distribution cabinets for holdingfiber optic telecommunications terminations and equipment.

BACKGROUND OF THE INVENTION

Fiber distribution cabinets are known for holding and managing fiberoptic cables, splices, and terminations for cables extending to and fromthe cabinets. In some cases, the cables extending to and from thecabinets are underground cables. In some systems, conduit is laidbetween a remote site and a cabinet and then optical fiber is blownthrough the conduit when needed at a later time.

There is a need for cabinets which hold and manage the fiber opticcables, splices, and terminations, as well as interfacing with theconduit through which blown fibers are provided.

SUMMARY OF THE INVENTION

The present invention relates to cabinets and methods including anenclosure which has a first cable entry and a second cable entry. Thecabinet includes structure within the interior for connecting the firstcable to the second cable. In one preferred embodiment, a plurality ofshelves or trays is provided for holding the connections, such as thesplices between the first and second cables. The trays also includeholders for holding the conduit including microducts which are used toreceive blown fiber as part of the first or second cables.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a fiber optic distributioncabinet, shown with both front and rear doors open;

FIG. 2 is a partial exploded front perspective view of the distributioncabinet of FIG. 1;

FIG. 3 is a front elevational view of the distribution cabinet of FIG.1;

FIG. 4 is a rear perspective view of the distribution cabinet of FIG. 1with portions removed;

FIG. 5 is a rear elevational view of the cabinet of FIG. 1, showingfeeder subunit cables routed to a splice drawer;

FIG. 6 is a top perspective of the splice drawer showing feeder pigtailsconnected to splice trays in the splice drawer;

FIG. 7 is a top view of the splice drawer of FIG. 6, showing the feedersubunit cables joined to the feeder pigtails at the splice trays;

FIG. 8 is a top view of one of the splice trays of the splice drawer ofFIG. 6, showing one fiber splice;

FIG. 9 is a top perspective view of a connector drawer of the cabinet ofFIG. 1, showing the feeder pigtails joined to splitter input cables at atermination arrangement;

FIG. 10 is a top view of the connector drawer of FIG. 9;

FIG. 11 is a front elevational view of the cabinet of FIG. 1, showingsplitter input cables routed from the connector drawer to one of thesplitter modules;

FIG. 12A is a front elevational view of a splitter chassis including twosplitter modules;

FIG. 12B is a front elevational view of the cabinet of FIG. 1, includingthe chassis of FIG. 12A with one splitter module;

FIG. 13 is a front elevational view of the cabinet of FIG. 1, showingsplitter output cables routed to a connector storage panel;

FIG. 14 is a front elevational view of the cabinet of FIG. 1, showingsplitter output cables routed to two connector panels;

FIG. 15 is an enlarged view of a portion of one of the connector panelsshowing a connection between a splitter output cable and a distributionpigtail;

FIG. 16 is a top view of one of the connector panels;

FIG. 17 is an enlarged perspective view of a lower portion of thecabinet of FIG. 1, showing clamping of a conduit to the cabinet, andincluding microducts extending from the conduit;

FIG. 18 is a front elevational view of the cabinet of FIG. 1, showingvarious conduits and microducts extending to microduct holders;

FIG. 19 is a top view of one of the shelves of the cabinet of FIG. 1,showing connections between distribution pigtails and fibers extendingfrom the microducts at splice trays;

FIG. 20 is a top view of one of the splice trays of the shelf of FIG.19, showing one fiber splice;

FIG. 21 is a front perspective view of one of the shelves;

FIG. 22 is a rear perspective view of the shelf shown in FIG. 21;

FIG. 23 is a schematic view showing the various elements of the cabinetof FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIGS. 1-4 and 23, one preferred embodiment of atelecommunications fiber distribution cabinet 10 is shown. Cabinet 10includes an enclosure 12 for housing connections between a first cable14 and a second cable 16. In one embodiment, first cable 14 is a feedercable, and second cable 16 is a distribution cable. As will be describedbelow, enclosure 12 houses the connections between individual opticalfibers associated with each of first and second cables 14, 16. Cabinet10 is also useful in interfacing with hollow conduit, such as ducts,which can be used for later insertion of optical fibers, such as with ablowing operation.

Cabinet 10 includes a base 17, first and second sides 18, 20, an openfront 22, and an open rear 24. First and second pivotally mounted doors26, 28 are mounted adjacent to open front 22 and open rear 24,respectively. Enclosure 12 defines an enclosed interior 30 whichreceives first and second cables 14, 16 and holds and manages theconnections between the cables.

Referring also now to FIGS. 5-22 in addition to FIGS. 1-4 and 23,cabinet 10 includes a first cable entry 32 through base 17. First cable14 can be clamped with a clamp 34. Typically first cable 14 is anunderground cable entering cabinet 10 from beneath base 17. Clamp 34 canbe mounted to an inner vertical panel 36 which further includes cableties 37 and a cable manager 38. Such devices are useful for guidingfirst cable 14 to the various interconnection structures within cabinet10.

Cabinet 10 also includes a second cable entry 50 allowing second cable16 to enter cabinet 10. In the illustrated embodiment, second cable 16is also an underground cable entering cabinet 10 from beneath base 17.Second cable 16 includes an outer conduit 52 with a plurality of innermicroducts 54. Conduit 52 is clamped with a clamp 56 to a clamp panel58. Microducts 54 are typically installed for later use when an opticalfiber interconnection is desired. Cable installation devices are knownwhich insert optical fibers into hollow ducts, such as through a blowingoperation which uses pressurized air to install the optical fiber in theduct. Cabinet 10 allows for initial placement conduit 52 with microducts54 where the optical fibers 60 are installed at a later date inmicroducts 54.

A plurality of trays or shelves 70 hold ends 62 of microducts 54 with amicroduct holder 200. Shelves 70 also hold fiber splices for joiningfibers 60 to further fibers connected to first cable 14, as will bedescribed below, thereby completing the connection between first cable14 and second cable 16.

Referring now to FIGS. 6-8 and 23, first cable 14 in the form of feedersubunit cables 80 enter splice drawer 100. Splice drawer 100 includes achassis 102 and a moveable tray 104. Moveable tray 104 holds one or moresplice trays 106. Splice trays 106 include splice chips 108 which holdthe individual splices 110 between feeder subunit cables 80 and feederpigtails 82.

Referring now to FIGS. 9, 10 and 23, feeder pigtails 82 are shown beingconnected to splitter input cables 84 in a connector drawer 120.Connector drawer 120 includes a chassis 122 and a moveable tray 124.Mounted on tray 124 is a plurality of terminations of 126. Terminations126 include a connector 128 on the end of each feeder pigtail 82 andeach splitter input cable 84 which are joined together in an adapter130.

Splice drawer 100 and connector drawer are mounted to panel 36 atmounting strips 39 which receives fasteners. Further features of splicedrawer 100 and connector drawer 120 are shown and described in greaterdetail in U.S. Pat. Nos. 6,438,310, 6,504,988, and 7,079,744, thedisclosures of which are hereby incorporated by a reference.

Referring now to FIGS. 11-14, splitter input cables 84 are shown beingsplit into splitter output cables 86 which are either stored in a fiberstorage device 150 (FIG. 13) or terminated to other cables at connectorpanel 160 (FIG. 14). Each splitter module 170 includes an input port 172and one or more output ports 174 in the illustrated embodiment. Forexample, each splitter module 170 can split a splitter input cable 84into a plurality of splitter output cables 86, such as a 1×32 splitter.Splitter modules 170 are mounted in a chassis 176 which mounts tomounting strips 39 with fasteners. A cable manager 180 helps manageslack associated with splitter output cables 86.

When splitter output cables 86 are not yet needed for connection todownstream equipment, storage panel 150 is used to hold each splitteroutput cable 86. Preferably, each splitter output cable 86 includes aconnector 128. Preferably, connector storage panel 150 can receive eachconnector 128, or a group of connectors, including a dust cap over anend of a ferrule associated with connector 128. Further features ofexemplarily connector storage panels 150 and holders are shown anddescribed in U.S. Pat. No. 7,218,827, the disclosure of which is herebyincorporated by reference.

When a downstream connection is desired, a splitter output cable 86 isremoved from connector storage panel 150 and connected to a front ofconnector panel 160. Referring now to FIGS. 15 and 16, connector panel160 includes a plurality of adapters 130 for joining two connectors 128.Once connected, splitter output cable 86 is optically linked to adistribution pigtail 88 which is led from connector panel 160 to one ofshelves 70. Connector panel 160 in the illustrated embodiment has achassis 163 mounted to mounting strips 39 with fasteners, and a pivotingpanel 164 for holding the adapters 130. A cable manager 182 (FIG. 4)manages distribution pigtails 88 between connector panels 160 andshelves 70.

Referring now to FIGS. 17-22, distribution pigtails 88 are joined tofibers 60 through splice tray 190 on each shelf 70. Each shelf 70includes a microduct holder 200 which holds an end 62 of one of themicroducts 54. Specifically, microduct holder 200 includes a pluralityof holes 202 which are sized to closely surround an exterior of eachmicroduct 54. The circular periphery defined at each hole 202 engages anexterior of the microduct 54 to frictionally hold the microduct relativeto shelf 70. In the illustrated embodiment, microduct holders 200 areshown positioned in a side plate 204 of each shelf 70. The holes 202 canbe punched from sheet metal. If desired, an insert can be mounted toshelf 70, or to a vertical panel adjacent to shelf 70 so as to providethe circular holes 202 separate from shelf 70. Also, a variety ofmicroducts 54 can be used. A differently sized microduct holder 200 isutilized for different microducts. For example, an outside diameter ofthe microducts can vary from 3 millimeters, to 5 millimeters, to 7millimeters. To facilitate insertion, an end 62 of each microduct 54 isprovided with a tapered shape (45 degree angle) so as to permit easierinsertion in each hole 202. This can be cut off square as desired afterinsertion. In the case of a 5 millimeter duct, a hole having a diameterof 0.189 inches+/−0/0.002 inches will allow insertion of each ductwithout excessive effort or damage to the duct, and then retain eachduct with sufficient retention force.

On a base 208 of each shelf 70 a tie device 210 can be provided fortying ends 62 of microducts 54 to each other or to each shelf 70. Base208 of each shelf 70 further includes cable radius limiters 212 formanaging the cables on each shelf 70. Shelf 70 further includes splicetray mounts 214 for holding splice trays 190 on shelves 70. Each splicetray 190 includes a splice chip 192 for holding a splice 194 used tojoin each distribution pigtail 88 to each fiber 60.

Each shelf 70 further includes a slot 220 for use in passing first cable14 from base 17 to splice drawer 100 located adjacent a top 21 ofcabinet 10. Shelves 70 further include an aperture 222 for allowingdistribution pigtails 88 to pass to the appropriate shelf 70 forconnection to the fibers 60 located on each shelf 70.

In this manner, microducts 54 can be installed to cabinet 10, and theblown fiber inserted later. It is anticipated that the blown fiber canbe inserted from either end of microduct 54, either at end 62, or at theremote end disposed at the remote site.

Cabinet 10 manages the feeder cables 14 and the duct 54 of thedistribution cable 16, so that a user can install blown fiber at a laterdate, and then make appropriate connection to the feeder cable, such aswith a splice on shelf 70. The other functions provided by cabinet 10also allow ease of use, such as the access provided by each of drawers100, 120, splitters 170, connector panel 160, as well as the variouscable managers.

1. A method of managing cable in a telecommunications system comprising:providing an enclosure including an interior, the interior receiving afeeder cable and a conduit including microducts; routing the feedercable to a splicing area including a plurality of horizontal shelves,each horizontal shelf including a cable splice tray and a microductholder, wherein the microduct holder defines a plurality of holes forholding at least some of the microducts; routing the conduit adjacent toone of the horizontal shelves, wherein the microducts are held by themicroduct holder.
 2. The method of claim 1, further comprising the stepof blowing a fiber through one of the microducts and splicing the fiberblown through one of the microducts to the feeder cable.
 3. The methodof claim 1, wherein the plurality of holes of each shelf includes aplurality of rows and columns of holes in a sheet metal plate.
 4. Themethod of claim 1, wherein each of the holes frictionally engages one ofthe microducts.
 5. The method of claim 4, wherein each hole defines acircular periphery that frictionally engages an exterior of themicroduct.